I realize that Blu-Ray discs cost $10-$15 more than standard DVDs, but they will rent out these discs hundreds of times.

Would the average Blu-ray disc last long enough to be rented hundreds of times? I've had a couple of fairly recent NetFlix BD releases recently that would not play they were scratched so badly, so I have to wonder what the actual average life-span is. I know they have machines to polish damaged discs but at some point the discs must be retired (re-sold or sent back to the distributor) right?